Of all the acts of heroism that have been rewarded with a Victoria Cross, it
is, perhaps, the most noble.

Sapper William Hackett spurned the opportunity to crawl to safety in order to remain behind to comfort a wounded comradePhoto: PAUL ARMIGER

By Jasper Copping

9:00AM GMT 08 Nov 2009

Entombed 40ft beneath the killing fields of the Western Front when the tunnel he was in caved in, Sapper William Hackett spurned the opportunity to crawl to safety in order to remain behind to comfort a wounded comrade, before a second collapse sealed the two men in forever.

Now, the full story of this extraordinary act can be told for the first time after the chance discovery of a diary written by another soldier, which chronicles the event. The unit's war diary from the time has been lost and the diary has provided the only known account of Sapper Hackett's "almost divine act of self sacrifice".

At 2.50am on June 22nd 1916 he and four other tunnellers were digging towards the German lines in the Givenchy sector, in northern France, when an enemy mine exploded, collapsing the tunnel they were in. Eventually, a rescue party dug its way towards them and made contact through a small hole, through which Sapper Hackett helped three comrades to safety.

However, with sanctuary beckoning and although himself unhurt, he refused to leave without the last man, seriously injured 22-year-old Thomas Collins, who was too wounded to get through the hole.

Repeated artillery barrages from the Germans forced the rescuers back to the surface, leaving the two men below. Eventually, the shaft collapsed, and rescue efforts had to be abandoned, leaving the two men to their fate below.

The newly-discovered diary was written by Sapper John French, who was in the same unit as Sapper Hackett, 254 Tunnelling Company, Royal Engineers, and was involved in the rescue attempts. It was found among the possessions of his sister, following her recent death, and given to the Redruth Old Cornwall Society Museum, where it has been studied by historians.

Its discovery follows another development, when battlefield archaeologists using ground-penetrating radar, pinpointed the location of the collapsed tunnel, ahead of the construction of a new memorial to commemorate Sapper Hackett and other British tunnellers, due to be unveiled next summer.

In understated fashion, the diary chronicles the "heart breaking" attempts, over the space of five days, to reach the men and the "heroic" decision by Sapper Hackett, from Nottingham, once the rescuers had reached the group, to remain behind.

On June 22, rescuers are able to make contact with the five men and speak to them through an air pipe. The diary reveals that among the threats the stranded men faced was drowning, as the rescuers had to pump air in and water out.

The next day, Sapper French wrote: "Those five men are still entombed. We have been working night and day trying to get them out. It is 25 feet to go & we are in 15, but it is very slow work owing to so much broken timber and running muck (loose earth or quicksand). They are still alive and we can speak to them."

On June 24th, Sapper French records that the team reached the men and were able to get three men out, as well as Sapper Hackett's fateful decision to remain behind. He wrote: "Got out three of the five men last night. One of the others [Thomas Collins] had some ribs broken & could not crawl through the very small hole that had been driven through. The other fellow [William Hackett] offered to stop in with him until they could make the hole bigger so they passed in some food to them. They had no sooner done that than there was another fall & they were entombed again."

The next day, he wrote: "Those two fellows still entombed. Had to start a new gallery to try & get to them but with the water & running muck it is a heart breaking job. We cannot get any answer from them now. Men are working hard at it night and day. Fritz keeps on sending over rifle grenades & trench mortars all the time."

The next day, he added: "Still trying to get through to those two men, but it is painfully slow, we can't get any answer from them."

On June 27th, he wrote: "Abandoned all hope of getting those two chaps out this morning & stopped all rescue work for the condition of the shaft was so bad as to endanger the lives of the men working down there and they think that they are both dead. That chap Hackett died a hero for he could have come out with the others but would not leave his injured comrade."

One extra detail provided by Sapper Hackett's VC citation were his words to the rescue team as he turned down the opportunity to save himself: "I am a tunneller and must look after the others first."

Peter Barton, an historian who has been researching the tunnellers for 30 years, said: "None of this was known until now. This is the only account of Hackett's action. Until now, it was a hidden, almost private act.

"I describe this as the most noble of all Victoria Crosses, because it involved no enemy action. It was not about the adrenalin rush of an attack, with shells bursting around, and so on.

"This was an act of heroism that occurred in silence and in darkness, 40ft below ground. This was an entirely different type of valour that was supremely noble. It was an almost divine act of self sacrifice. It is absolutely unimaginable."

Geoffrey Hackett, 64 and from Nottingham, who is a great great nephew of Sapper Hackett, said: "The diary really brings it home, what happened. It tells the grim story with a day by day account and shows how people were feeling at the time. You can't make the story any more dramatic than it actually was.

"But I like to think that my relative's VC is to help remember that there were a lot of tunnellers who weren't remembered because their work had to be secret."

Mr Barton and archaeologists from Glasgow University have located the collapsed mine and the historian is currently involved in raising money for a memorial in honour of those involved in the "underground war".

Both sides made extensive use of tunnels in an effort to break the stalemate of the Western Front. So-called "fighting trenches" were dug to plant explosives beneath the enemy positions.

Mr Barton said: "Tunnelling was the most barbaric form of warfare there was. It was secret and little known about at the time and that remains. We are only now hearing the stories."